Infra-red absorption glass for a reed switch

Abstract

An infra-red absorption glass for a reed switch is suitable for encasement of a reed switch using magnetic wire members made of Fe—Ni based alloy (52 alloy). In the infra-red absorption glass, an infra-red transmittance at a wavelength of 1050 nm is not greater than 10% for a thickness of 0.5 mm and the content of Cl in the glass is not greater than 150 ppm. In the glass, a coefficient of thermal expansion in a temperature range between 30 and 380° C. is preferably 85-100×10−7/° C. In addition, the infra-red absorption glass preferably has a composition consisting essentially of, by weight percent, 60-75% of SiO2, 1-10% of Al2O3, 0-10% of B2O3, 3.5-10% of RO (R being one or more selected from Ca, Mg, Ba, Sr, and Zn), 0.5-5% of Li2O, 8-17% of Na2O+K2O, 2-10% of Fe3O4.

Dependencies are inferred from the claim text.